Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/26—Oils; Viscous liquids; Paints; Inks
  • G01N33/28—Oils, i.e. hydrocarbon liquids
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/26—Oils; Viscous liquids; Paints; Inks
  • G01N33/28—Oils, i.e. hydrocarbon liquids
  • G01N33/2888—Lubricating oil characteristics, e.g. deterioration
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N11/00—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties
  • G01N11/10—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by moving a body within the material
  • G01N11/16—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by moving a body within the material by measuring damping effect upon oscillatory body
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
  • G01N29/02—Analysing fluids
  • G01N29/036—Analysing fluids by measuring frequency or resonance of acoustic waves
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2291/00—Indexing codes associated with group G01N29/00
  • G01N2291/02—Indexing codes associated with the analysed material
  • G01N2291/025—Change of phase or condition
  • G01N2291/0258—Structural degradation, e.g. fatigue of composites, ageing of oils
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2291/00—Indexing codes associated with group G01N29/00
  • G01N2291/02—Indexing codes associated with the analysed material
  • G01N2291/028—Material parameters
  • G01N2291/02818—Density, viscosity
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2291/00—Indexing codes associated with group G01N29/00
  • G01N2291/04—Wave modes and trajectories
  • G01N2291/042—Wave modes
  • G01N2291/0427—Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever

Definitions

• the invention relates to an oil quality sensor according to the preamble of claim 21, method for determining the oil quality and the use of a sensor.
• Motor oils have developed over time into high-tech products that are essential to enable high engine performance.
• "Motor oils” represent a collective name for base oil components made from mineral oil, hydrocrackants and synthetic components. Motor oils also contain additives that are added as a ready mix ("package"), as well as viscosity index improvers (VI).
• the engine oils serve as lubricants for the engines and as a cooling and sealing medium. Furthermore, they should clean and keep all engine parts clean.
• the VI improvers bring about a more favorable viscosity-temperature behavior than the pure base oils have.
• the proportion of additives and Vl improvers is usually between 5 and 25% depending on the requirements placed on the oil.
• oils age in the course of their use, with the additive components and the Vl improvers primarily being degraded (consumed). Unused, partially oxidized and polymerized fuel components have a significant share in oil aging. Thus, oil aging is caused by the effects of temperature and reactive combustion products (radicals) as well as by exceeding the
• REPLACEMENT BLA ⁇ (RULE 26) Oil dispersibility for solids and aging products. As a result, the properties of the oils required for trouble-free operation of the engines are sometimes drastically deteriorated. An increased viscosity has z. B. at the start of an extended transport of the oil to the lubrication points resulting in an increase in wear.
• the consumption of the dispersing additives results in a deterioration in the ability of the oils to keep the engines clean, particularly at critical lubrication points, such as in the area of the piston rings / grooves and top land, as well as a deterioration in the prevention of deposits on valves and in the valve train.
• the object of the present invention is to provide a sensor which can also carry out measurements on-board an internal combustion engine, the sensor being intended to determine the aging of an oil largely reliably and without interference.
• the subclaims show preferred embodiments with which particularly inexpensive sensors, sensor uses and oil quality determinations can be carried out. If reference is made below to a layer, a surface, a volume or a material, this reference applies mutatis mutandis to the entire group and to all uses, methods and sensors of this invention.
• the layer is a material firmly connected to a substrate.
• the determination of the analyte according to the invention is generally not only qualitative, but in particular at least semi-quantitative. This means that the determination of the analyte also results in an exact or estimated determination of the concentration or quantity of the analyte.
• the reaching of the determination threshold value can be used in connection with a mathematical method (e.g. time lapse) for signaling (the oil change).
• the senor can be used according to the invention in all liquids in which there is a material change in the composition, ie in which at least one component increases or decreases.
• the sensor is preferably used for the characterization of a complex liquid, ie in a liquid which contains several components which are unknown in terms of structure and quantity. In particular, there is usually no repeatability of the exact composition of the liquid, e.g. B. because the composition of the liquid is due to a (not manageable) variety of influences.
• the sensor is used particularly advantageously in an oil-containing liquid, preferably in a liquid which contains at least 30% and in particular at least 50% oil. In addition to the oil, various other components can also be present, which can also be recognized by the sensor if necessary.
• the sensor is preferably designed for one or more constituents of the oil which decrease as the oil (or liquid) is used; however, it is also possible to design the sensor for an increase in one or more constituents of the liquid. Such an increase is e.g. B. with increasing acidity with the aging of the oil before, ie, the increase in acidic compounds can also be determined.
• the sensor is advantageously designed for one or more main components of the liquid, ie those components which make up the main proportion by weight of the liquid, for example the oil composition.
• the acidic changes in the aging of an engine oil described above are detectable by IR spectroscopy.
• a sensor in the measurement according to the invention which can repeatedly store and remove at least one component of the liquid, advantageously according to the concentration of this component.
• the sensor used according to the invention differs by at least one of the following features:
• the component of the liquid has a molecular weight> 150, in particular> 200;
• the component of the liquid is essentially absorbed or adsorbed on the sensor
• the (determined) component of the liquid is not cationic, in particular not ionic;
• An interface potential, electrochemical potential and / or hydrogen potential is not determined as a characteristic variable.
• the component is chosen so that it changes in the course of the use of the liquid in terms of its affinity for the sensitive layer, usually this is achieved by a change in the concentration of the substance in the liquid through the use of the same.
• one (or more) constituent of the liquid can be measured particularly advantageously by the constituent being embedded in or detached from the sensitive layer, with a change in the weight of the sensitive layer taking place.
• the incorporation can also be referred to as a volume effect, ie the incorporation of the analyte or analytes takes place at least up to a certain layer thickness, essentially proportional to the layer thickness.
• one (or more) analyte (a component) in an oil and / or one (or more) oily analyte is determined by the incorporation of the analyte (s) in the sensitive layer.
• a motor oil such as is used, for example, in internal combustion engines, is particularly suitable as analyte and / or oil.
• the analyte is advantageously at least a component of a new motor oil, but it can also be a component of the waste oil that forms when the motor oil is used, in particular an oxidation product.
• the analyte preferably has an aliphatic residue, as is usually present in mineral and / or synthetic motor oils.
• Such hydrocarbon residues usually have a molecular weight between 300 and 3,000.
• the sensitive layer of the sensor is particularly advantageously constructed from a polymer.
• Particularly suitable polymers are polyurethanes and / or modified polyurethanes, for example those in which the OH component is at least partially replaced by an NH 2 component.
• basic components are incorporated into the polymer structure. This can be done, for example, by using basic monomers or prepolymers with basic residues, the basicity advantageously being retained during the formation of the polymer.
• Such a basic monomer is, for example, triethanolamine N (CH2CH2 ⁇ H) 3, which acts as a crosslinker and whose tertiary amine group is retained during the polymerization to give the polyurethane.
• triethanolamine N CH2CH2 ⁇ H
• the adaptation to waste oil takes place, ie the polymerization takes place in the presence of waste oil, which can subsequently be detached from the finished polymer.
• the nitrogen contained in the triethanolamine can then undergo polar interactions with the acidic components in the waste oil and thus extract these components from a mixture, even in the presence of certain amounts of unused oil.
• the triethanolamine in the layers thus obtained generally offers polar interaction centers for analyte molecules with adapted properties.
• the adaptation to the analyte generally takes place advantageously in that the layer is formed together with the analyte, for example by mixing an engine oil with the layer former, in particular a monomer or prepolymer.
• the layer composition is preferably selected such that the analyte, like the entire liquid, is inert to the layer, i. H. this neither degrades nor is it chemically altered in any other way.
• the senor is advantageously used together with a non-sensitive sensor (measuring element of the same construction as the sensor, but without the sensitive properties for a component of the liquid), which serves as a reference.
• a non-sensitive sensor measuring element of the same construction as the sensor, but without the sensitive properties for a component of the liquid
• This enables a simple and safe measurement setup.
• It is also very particularly advantageous to use differently sensitive sensors together, especially in connection with a non-sensitive sensor.
• One sensor is then designed for the detection of new oil, and the other sensor is designed for the detection of old oil.
• These differently sensitive sensors can mutually serve as a reference, so that changes in viscosity can be averaged out.
• the oil sensor can be used for a wide variety of oils (or other liquids).
• the failure of a sensor or a possible reduced sensitivity of a sensor such as can occur when using a wide variety of oils, can also be detected, which ensures particularly high process reliability.
• the measurement itself is preferably carried out by vibrating the layer, and a dielectric effect of the layer can also be used, for example, as a measuring principle.
• the layer is advantageously applied to a vibrating crystal (quartz crystal), which is then excited to vibrate.
• the layer becomes heavier in accordance with the load, which changes the vibration behavior. This in turn can be used to draw conclusions about the loading quantity.
• Temperature sensor used because the viscosity (especially with engine oil) is strongly temperature-dependent.
• the temperature-dependent viscosity behavior of the liquid phase can be stored, for example, in a map, via which the temperature correction of the measured values is then carried out. Alternatively or additionally, the measurement can also be carried out only at one or more fixed temperatures.
• the use of the sensor also includes evaluation electronics via which the sensor is operated on the one hand and on the other hand the sensor signal is converted to the desired information.
• the information can be an indication of when the engine oil change is due.
• any layer can be used for the present invention which contains a matrix with cavities and / or diffusion channels which connect to one another determining component of the liquid (analyte) are adapted (adapted), ie storing the analyte according to its concentration (at a high concentration) or removing it (at a low concentration of the analyte in the liquid).
• molecular embossing such molecularly embossed layers being used essentially only in gases.
• Such molecularly embossed layers can be produced industrially and inexpensively.
• the generation of the sensor layer for example by a polymerization process, is carried out
• the analyte molecules leave their imprint in the matrix during the polymerization or curing and can be evaporated or flushed out of the (polymeric) network after completion of the reaction
• the quality of the molecularly shaped layers depends on many influences, in particular on the choice of layer material (polymer), duration of polymerization, solvent Rapid in the production of layers, temperature, crosslinker content etc.
• This manufacturing process leaves in the chemically sensitive layer adapted to the analyte cavities and diffusion channels, which are predestined for the reassembly of the analyte.
• This imprinting leads to analyte-specific interactions analogous to the key-lock principle, corresponding to the concentration of the analyte.
• This embossing process can be carried out not only with a chemically pure analyte, but also with an analyte mixture of complex composition. It is therefore also possible to characterize the diverse aging processes in engine oils with sensors manufactured in this way.
• such a sensitive layer can, for example, by polymerizing a polyurethane with a certain proportion of crosslinker molecules in the presence of e.g. B.
• fresh motor oil for example for petrol engines; mineral oil-based and / or synthetic.
• cavities adapted to the components of the fresh motor oil remain in the polymer matrix.
• infrared spectroscopy it can be shown that these cavities incorporate remarkably selectively new oil.
• the selectivity is less when embossing with used oil, ie small amounts of new oil are also stored, whereby the response (e.g. weight change; electronic signal) is lower.
• FIG. 2 IR spectra of a non-imprint sample after various work steps, CH 2 / CH 3 / OH stretching vibrations;
• FIG. 3 IR spectra of an imprint sample after the individual work steps
• FIG. 4 IR spectra of an imprint sample of an amine-containing polymer after various work steps
• FIG. 5 shows the temperature dependence of the frequency response of an uncoated QMB in old and new oil
• FIG. 6 shows the frequency response of a QMB embossed with new oil when changing from new oil to old oil
• FIG. 7 shows a comparison of the frequency responses of mass-sensitive and non-mass-sensitive coated QMB
• FIG. 8 IR spectra of fresh and used Otto engine oil
• Figure 9 shows a comparison of the frequency responses of new oil and used oil-influenced QMB.
• the chemically sensitive layers are produced by molecular embossing of different polyurethanes. The following chemicals are used:
• Diphenylmethane diisocyanate e.g. Synt. (Mixture of 70% diisocyanate and 30% triisocyanate);
• Each of the synthesized polyurethanes contains one of the isocyanates and a mixture of the two alcoholic components in a stoichiometric ratio.
• the proportion of phloroglucin in the alcoholic component determines the degree of crosslinking.
• a favorable degree of cross-linking for imprints (for the re-storage of the analyte) is approx. 60% (depending on the polymer generally 20 - 85%).
• the individual components are dissolved in THF together with the appropriate amount of new oil.
• This mixture can be applied directly to glass plates or quartz plates for measurement using FT-IR or to quartz crystals.
• REPLACEMENT BUTT (RULE 26) Monomer mixture and thus 23.1% share of the total mass of the matrix) are dissolved in 1 ml THF.
• Used petrol was weighed into Eppendorf vessels (62.8 mg with 30% oil content in the layer, 48.9 mg for 25% and 36.7 mg for 20%) and dissolved in 0.5 ml THF.
• the alcoholic components were then first added to this solution using a Gilson pipette, and the isocyanate was added shortly before application.
• the mixtures are composed as follows:
• Isocyanate 231 ⁇ l solution
• the two trifunctional components phloroglucin and triethanolamine were mixed in the required ratio (e.g. 10% TEA in the view ⁇ 10 ⁇ l TEA solution and 90 ⁇ l phloroglucin solution).
• the plates polymerized out overnight are measured in a FT-IR device (Perkin-Elmer FTIR 2000) against an empty quartz plate as a blank.
• the symmetrical and antisymmetric methylene vibrations at 2 856 cm- 1 and 2 921 cm- 1 are used for interpretation.
• the main measuring points are obtained after the following steps:
• the reaction mixture is applied to the quartz crystal.
• the so-called spin-coating method in which the sensor rotates at 200 - 400 rpm during the polymerization (depending on the viscosity of the layer material).
• the layer thickness is approximately 1.5 ⁇ m, which produces a frequency swing of approximately 75 kHz.
• the mass-sensitive measurement is carried out with a network analyzer, whereby a high frequency of variable frequency is applied to the coated quartz component and so that
• the increase in viscosity induces a lowering of the frequency, which - in the case of chemically sensitive coatings - is partially compensated for by a mass effect.
• the latter is generated by the diffusion out of molecules previously embedded in the layers.
• the viscosity effect is 16,000 Hz, with sensitively coated components the frequency deviation varies between 11,000 and 15,000 Hz depending on the polymer layer.
• the mass effect is therefore 1,000 to 5,000 Hz depending on the layer used.
• FIGS. 2 to 4 show the IR spectra of three polymers recorded after the individual work steps.
• a polymer produced without embossing (FIG. 2) is compared with a polymer embossed with fresh oil from an identical material (FIG. 3) and an amine polymer embossed with fresh oil (FIG. 4).
• the IR spectra are carried out according to the following process steps:
• ERSATZBU ⁇ (RULE 26) 3. Storage of the polymer in Otto-Neuöl for twelve hours with subsequent rinsing of the surface layers;
• the intensities of the aliphatic peaks decrease when the imprint is rinsed out, so a large part of the oil can be removed from the polymer matrix.
• the intensities almost rise again to the initial value, so the new oil is stored again in the polymer matrix (the same spectra are obtained when the new oil is repeatedly stored and removed).
• the spectra also show that waste oil (4) is not stored in the polymer structure, the IR spectrum corresponds to that of the sample rinsed with n-heptane.
• the polymer is a pure polyurethane layer.
• the relevant signal is at about 2900 wave numbers (the broad bands at about 3200 cm- 1 represent primarily oscillations' of acidic hydrogens group).
• the same material behaves quite differently when it is polymerized together with fresh oil (FIG. 3).
• FIG. 5 shows the temperature dependence of the resonance frequency of an uncoated QMB in used oil 22 or in new oil 21.
• the frequency swing 23 of the quartzes immersed in the respective oil is 16 kHz when new oil is used in used oil. Similar values are with
• REPLACEMENT BUTT (RULE 26) Obtain crystals that are coated with polymers that cannot incorporate oil (non-embossed polymers, non-imprint sample). A linear relationship between the logarithm of the frequency swing and the reciprocal absolute temperature can be observed. Quartz crystals with non-sensitive polymer layers (non-imprint) result in straight lines which are shifted in parallel and whose gradients differ by a maximum of 10%. It follows that the frequency sweeps measured are pure viscosity effects and not mass effects.
• the frequency swing that can be observed when transferring a QMB (quartz micro balance) of new oil in old oil loaded with a sensitive layer (imprint sample) produced by molecular embossing is initially 2 to 3 kHz lower at a temperature of 50 ° C than for a non-imprint quartz. Depending on the polymer layer, the frequency swing can be even smaller.
• FIG. 6 shows a frequency swing 25 of 11 kHz for a quartz with a sensitive layer, i. that is, this frequency shift 25 is 5.0 kHz below that of an uncoated quartz (a quartz with a non-imprint layer can also be used here).
• the quartz which is not provided with a sensitive layer, reacts almost exclusively to the different viscosities of new oil 31 and old oil 32, without taking their chemical compositions into account.
• the frequency response ⁇ f is 16 kHz.
• an amount of 11 to 14 kHz (depending on the sensitive layer) is obtained (see above). H. approx. 2 to 5 kHz less. This amount results from the mass effect, i.e. H. the difference in weight of the sensitive layer loaded with new oil 33 and the detachment of the new oil 33 from the sensitive layer when it is stored in old oil 32.
• REPLACEMENT BUTT (RULE 26) Mass effect ⁇ m.
• the aging of an engine oil can be continuously monitored by increasing the mass effect, the change in viscosity, which ranges from an increase to a decrease, being taken into account by the reference.
• FIG. 9 shows the comparison between a quartz coating 42 embossed with old oil and a quartz coating 41 embossed with new oil.
• the quartz 41 embossed with new oil shows a frequency shift of 16 kHz in new oil, which decreases to 13 kHz in old oil.
• the quartz 42 embossed on used oil shows a frequency shift of 16 kHz in fresh oil, which increases to 18 kHz in used oil.
• the oil quality is advantageously determined by means of a quartz coated with a sensitive layer.
• the sensitive layer has a surface adapted to at least one oil component, which is predestined for repeated storage and removal of the oil component in accordance with the concentration of the oil component.
• the oil component is present, it is embedded in the sensitive layer, which causes the resonance frequency to drop due to a mass effect, an effective increase in the component thickness or mass. Due to the aging of the oil the component that is in the sensitive
• REPLACEMENT BUTT (RULE 26) Layer deposits, which increases the resonance frequency.
• a non-sensitive layer is used as a reference, via which the viscosity effect of the oil on the vibration of the quartz is determined.

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• Chemical & Material Sciences (AREA)
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• General Physics & Mathematics (AREA)
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• Chemical Kinetics & Catalysis (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Medicinal Chemistry (AREA)
• Food Science & Technology (AREA)
• General Chemical & Material Sciences (AREA)
• Acoustics & Sound (AREA)
• Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
• Lubrication Details And Ventilation Of Internal Combustion Engines (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)

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• 1997
  • 1997-10-17 DE DE59712425T patent/DE59712425D1/de not_active Expired - Lifetime
  • 1997-10-17 CN CNB971809275A patent/CN1165762C/zh not_active Expired - Fee Related
  • 1997-10-17 KR KR1019997003649A patent/KR100651891B1/ko not_active Expired - Fee Related
  • 1997-10-17 JP JP51999098A patent/JP4071289B2/ja not_active Expired - Fee Related
  • 1997-10-17 AU AU50509/98A patent/AU5050998A/en not_active Abandoned
  • 1997-10-17 EP EP97913159A patent/EP0934520B1/de not_active Expired - Lifetime
  • 1997-10-17 WO PCT/EP1997/005748 patent/WO1998019156A1/de not_active Ceased
• 1999
  • 1999-04-26 US US09/299,126 patent/US6223589B1/en not_active Expired - Fee Related

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